Fly about 2,600 light-years to Hubble Space Telescope imagery of the Cygnus loop nebula. See images from 2001 and 2020.

A set of instruments shut off almost 50 years ago are still producing useful results. It's the seismometers left by the ...

If all volcanoes erupted together, the planet would be plunged into darkness as ash clouds blocked the Sun and global cooling ...